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[vsnet-campaign-dn 17564] ASASSN-25fj; new SU UMa-type dwarf nova, most likely WZ Sge subtype
by Yusuke Tampo 11 Jan '26

11 Jan '26

ASASSN-25fj; new SU UMa-type dwarf nova, most likely WZ Sge type ASASSN reported the discovery of ASASSN-25fj on 2026-01-1.19 UT. The observed maximum was approximately at 12.2 mag on 2025-12-25.0 UT according to ASASSN. https://asas-sn.osu.edu/sky-patrol/coordinate/ec92b0f6-1377-450b-b464-7fbe3… The likely counterpart is GALEX J050001.2-571430 (NUV=21.5(2) mag) and DES J050001.26-571430.1 (g=21.278(9) mag). Thus the outburst amplitude is ~9mag. Lesedi telescope at the SAAO and Josch Hambsch have reported the time-resolved observations of ASASSN-25fj. Its light curve after 2026-01-03 shows single-peaked ordinary superhumps with a period of ~0.0556 d and an amplitude of > 0.1 mag. Hence, ASASSN-25fj is a new SU UMa-type dwarf nova. Given its large outburst amplitude and short superhump period, it most likely belongs to the WZ Sge subtype. Continuous observations are encouraged. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17562] TCP J16425922+2621020: a large amplitude CV candidate, likely a WZ Sge-type dwarf nova
by Yusuke Tampo 27 Dec '25

27 Dec '25

TCP J16425922+2621020: a large amplitude CV candidate, likely a WZ Sge-type dwarf nova Tadashi Kojima reported the discovery of TCP J16425922+2621020 on 2025 12 26.8538 UTC at 13.0 mag (unfiltered). http://www.cbat.eps.harvard.edu/unconf/followups/J16425922+2621020.html The likely counterpart is 3"-away Gaia DR3 1301247792154799488, G=20.044(8) mag at 674 (-144/+248) pc. Thus, the absolute magnitudes in quiescence and outburst are ~10.9(7) and ~3.9(7) mag, respectively. This is also recorded in the Gaia white dwarf candidate catalogs (e.g., Gentile et al. 2021). http://vizier.cds.unistra.fr/viz-bin/VizieR?-source=&-out.add=_r&-out.add=_… Given its large outburst amplitude of ~7 mag, no previous outbursts, and possible white dwarf-dominated spectral energy distribution in quiescence, TCP J16425922+2621020 is most likely a WZ Sge-type dwarf nova in outburst. Although time-resolved observations are almost impossible for now due to its RA=16hr, this might be a nice target for future observations. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17561] ASASSN-22nd (=AT2025ahnc= ZTF25acibbkf =ASASSN-25fb); a new fast-decaying outburst
by Yusuke Tampo 19 Dec '25

19 Dec '25

ASASSN-22nd (=AT2025ahnc= ZTF25acibbkf =ASASSN-25fb); a new fast-decaying outburst GOTO, ZTF, and ASASSN have detected a new outburst from a known CV candidate ASASSN-22nd. https://vsx.aavso.org/index.php?view=detail.top&oid=2345330 https://www.wis-tns.org/object/2025ahnc https://lasair-ztf.lsst.ac.uk/objects/ZTF25acibbkf/ https://asas-sn.osu.edu/sky-patrol/coordinate/19517db9-fb36-4d9c-a94d-2ca87… This outburst shows a fast decay, approximately 1 mag/d. Considering its large amplitude(>7mag), relatively short outburst cycle (~3 years), and fast decay of the outburst, this outburst could be a precursor outburst of a dwarf nova superoutburst, or even from an AM CVn star. Although the system is currently faint (~18.5 mag in ATLAS), if the system returns to a bright state, time-resolved photometries will be encouraged. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17557] ASASSN-25eq: new WZ Sge-type dwarf nova, likely a period bouncer
by Yusuke Tampo 17 Dec '25

17 Dec '25

ASASSN-25eq: new WZ Sge-type dwarf nova, likely a period bouncer ASASSN discovered ASASSN-25eq on 2025-11-13.18 UT at 15.07 mag. Then it brightened to g=14.0 mag on 2025-11-15. The VSX lists g=21.9 mag as the counterpart, hence the outburst amplitude is ~8 mag. https://vsx.aavso.org/index.php?view=detail.top&oid=10868208 https://asas-sn.osu.edu/sky-patrol/coordinate/579ca10e-176d-4c3b-958f-03a39… Josch Hambsh and Berto Monard have reported the time-resolved observations of ASASSN-25eq. The light curve shows a 1-mag dip around 2025-11-25 UT. After this dip, clear superhumps are present, with a period of ~0.0645 d. There is no clear modulation before the dip. Thus, ASASSN-25eq is a new WZ Sge-type dwarf nova, with a double-superoutburst feature often observed in a period bouncer system. See e.g. https://ui.adsabs.harvard.edu/abs/2018PASJ...70...47K/abstract Given the absence of clear early superhumps, ASASSN-25eq is presumably a face-on system. A spectrum taken with the Mookodi/Lesedi telescope on 16 Nov. is dominated by Balmer absorption lines, which supports this interpretation. Time-resolved observations are encouraged. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17559] TCP J07454958-2442056: most likely a WZ Sge-type dwarf nova
by Yusuke Tampo 15 Dec '25

15 Dec '25

TCP J07454958-2442056: most likely a WZ Sge-type dwarf nova TCP J07454958-2442056 was discovered by Yuji Nakamura on 13th Oct 2025 at 14.0 mag (unfiltered). According to VSX, the outburst amplitude is ~8.2 mag. https://vsx.aavso.org/index.php?view=detail.top&oid=10868099 Josch Hambsch and Sjoerd Dufoer have reported the time-resolved observations of this source. The light curve shows possible superhumps with a period of ~0.055 d, although I cannot conclude due to its faintness and 1-d aliases. Given its large outburst amplitude, almost 40-d outburst duration, and short superhump period, TCP J07454958-2442056 is most likely a new WZ Sge-type dwarf nova. Note that the system has already faded below the detection level of ATLAS. https://fallingstar-data.com/forcedphot/queue/3502597/ Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17558] ASASSN-25en: new SU UMa-type dwarf nova
by Yusuke Tampo 02 Dec '25

02 Dec '25

ASASSN-25en: new SU UMa-type dwarf nova ASASSN discovered ASASSN-25en on 2025-11-03 UT at 14.94 mag. The outburst amplitude in the VSX is ~7.5 mag. https://vsx.aavso.org/index.php?view=detail.top&oid=10868163 Josch Hambsch and Itoh-san have reported the time-resolved observations. The light curve after 2025-11-11 UT shows a single-peaked superhump with a period of either 0.06003(3) or 0.06390(3) d. Thus, ASASSN-25en is a new SU UMa-type dwarf nova. The rapid decline from the outburst was observed around 2025-11-21 UT. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-campaign-dn 17556] TCP J06364062+3318310: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 26 Nov '25

26 Nov '25

Dear colleagues, TCP J06364062+3318310 was discovered by K. Sokolovsky et al. (NMW Survey) on 2025 Nov 17.99 at mag 13.6CV. The quiescent counterpart is a 21.3 r mag star, implying an outburst amplitude of ~8 mag. I have just completed the analysis of my unfiltered CCD time-series observations of TCP J06364062+3318310, obtained on 2025 Nov 25/26 at CBA Extremadura Observatory. The data were acquired under clear skies with a 0.40-m f/5.1 telescope and a Moravian G2-4000 CCD camera. I also obtained observations on several nights prior to Nov 25/26, but those did not reveal any obvious modulation. In contrast, the Nov 25/26 light curve clearly shows regular superhump modulations with an amplitude of 0.30 mag. A period analysis using ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0661 +/- 0.0008d. The object was measured at mag CV = 15.3 on Nov 26th. Image calibration and photometry were carried out using the latest release of Phoranso, which enabled simultaneous photometry of several additional variable stars in the same field of view. These results establish TCP J06364062+3318310 as a new SU UMa-type dwarf nova. Further follow-up observations are strongly encouraged to refine the superhump period and study its evolution. I will submit my observations to AAVSO, CBA and VSNET for further analysis. With kind regards, Tonny --- Tonny Vanmunster CBA Belgium Observatory CBA Extremadura Observatory http://www.cbabelgium.co <http://www.cbabelgium.com/> m PERANSO : The Light Curve and Period Analysis Software http://www.peranso.co <http://www.peranso.com/> m PHORANSO: Photometric Reduction and Analysis Software http://www.phoranso.com <http://www.phoranso.com/>

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[vsnet-campaign-dn 17555] TCP J21314718+3825463: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 15 Nov '25

15 Nov '25

Dear colleagues, TCP J21314718+3825463 was discovered by XOSS (Xingming Observatory Sky Survey) on 2025 Nov 07.6 at mag 14.70C. The quiescent counterpart is a 22.5 g mag star, implying an outburst amplitude of ~8 mag. I have just completed the analysis of my unfiltered CCD observations of TCP J21314718+3825463, obtained on 2025 Nov 11/12 and Nov 14/15 at CBA Extremadura Observatory. The data were acquired under clear skies with a 0.40-m f/5.1 telescope and a Moravian G2-4000 CCD camera. The Nov 11/12 light curve did not reveal any obvious modulation. However, the Nov 14/15 light curve clearly shows regular superhump modulations with an amplitude of 0.23 mag. A period analysis performed with ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0567 +/- 0.0016d. The object was measured at mag CV = 16.0 on Nov 15th. Image calibration and photometry were carried out using the latest release of Phoranso, which enabled simultaneous photometry of several additional variable stars in the same field of view. These results establish TCP J21314718+3825463 as a new SU UMa-type dwarf nova. Further follow-up observations are strongly encouraged to refine the superhump period and study its evolution. I will submit my observations to AAVSO, CBA and VSNET for further analysis. With kind regards, Tonny --- Tonny Vanmunster CBA Belgium Observatory CBA Extremadura Observatory http://www.cbabelgium.co <http://www.cbabelgium.com/> m PERANSO : The Light Curve and Period Analysis Software http://www.peranso.co <http://www.peranso.com/> m PHORANSO: Photometric Reduction and Analysis Software http://www.phoranso.com <http://www.phoranso.com/>

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[vsnet-campaign-dn 17554] TCP J00534786+1617214: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 10 Nov '25

10 Nov '25

Dear colleagues, TCP J00534786+1617214 (aka ASASSN-25ei) was discovered by Y. Nakamura, Japan on 2025 Nov 1.5 at mag 14.4 U. The quiescent counterpart is a 22.0 g mag star, implying an outburst amplitude of ~7.6 mag. I have just completed the analysis of my unfiltered CCD observations of TCP J00534786+1617214, obtained on 2025 Nov 08/09 at CBA Belgium Observatory. The data were acquired under clear skies with a 0.40-m f/10.0 telescope and a QHY-268M CMOS camera under clear skies. The light curve clearly exhibits regular superhump modulations with an amplitude of 0.19 mag. Period analysis with ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0624 +/- 0.0010d. The object was measured at mag CV = 15.5 on Nov 08th. Image calibration and photometry were performed with the latest release of Phoranso. These results establish TCP J00534786+1617214 as a new SU UMa-type dwarf nova. Follow-up observations are encouraged. I will submit my observations to AAVSO, CBA and VSNET for further analysis. With kind regards, Tonny --- Tonny Vanmunster CBA Belgium Observatory CBA Extremadura Observatory http://www.cbabelgium.co <http://www.cbabelgium.com/> m PERANSO : The Light Curve and Period Analysis Software http://www.peranso.co <http://www.peranso.com/> m PHORANSO: Photometric Reduction and Analysis Software http://www.phoranso.com <http://www.phoranso.com/>

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[vsnet-campaign-dn 17551] 1eRASS J072044.9-402838 = PNV J07204545-4028357 = ASASSN-25ee: new SU UMa-type dwarf nova, likely WZ Sge-type
by Yusuke Tampo 05 Nov '25

05 Nov '25

1eRASS J072044.9-402838 = PNV J07204545-4028357 = ASASSN-25ee: new SU UMa-type dwarf nova, likely WZ Sge-type 1eRASS J072044.9-402838 was originally identified as a CV candidate in Rodriguez et al. (2025), G = 19.2 mag at ~267 pc, hence its absolute magnitude of ~12 mag. https://vsx.aavso.org/index.php?view=detail.top&oid=10868116 https://ui.adsabs.harvard.edu/abs/2025PASP..137a4201R/abstract ASASSN and John Seach discovered its 2025 outburst, peaking at ~11.0 mag around 20th October. https://www.astronomy.ohio-state.edu/asassn/transients.html http://www.cbat.eps.harvard.edu/unconf/followups/J07204545-4028357.html We, the SAAO team, obtained the time-resolved photometries and a snapshot spectrum of 1eRASS J072044.9-402838 on 3rd Nov. The light curve shows likely superhumps with a rough period of ~0.059 d. The spectrum shows Balmer absorption lines from the accretion disk and a superposed narrow emission component in Hα. Hence, 1eRASS J072044.9-402838 is now confirmed as (at least) a SU UMa-type dwarf nova, and probably a WZ Sge-type dwarf nova, considering its large outburst amplitude, long outburst duration, and short superhump period. Further time-resolved observations are encouraged to establish its superhump period and changes. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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